Retainer for rotary power tools



I United States a t 2,890,072 RETAINER FOR ROTARY POWER TOOLS Frank A. Kaman, Aurora, and Paul E. Vega, Glen Ellyn, Ill., assignors to Thor Power Tool Company, Aurora, 11]., a corporation of Delaware Application July 10, 1956, Serial No. 597,045

1 Claim. (Cl. 287-53) This invention relates to spindles for power tools and more particularly to retaining means for rotary tool spindles whereby devices such as socket members and the like for engaging work may be detachably secured to the spindle.

Rotary power tools such as nutsetters, impact wrenches, and the like have been commonly provided with spindles projecting therefrom at their forward ends beyond the toolcasings. In order to secure to the spindle various attachments such as socket members and the like by which the tool may apply its driving torque to a piece of work, it has been customary to provide various types of retaining means on the spindle square and one of the most common types has been a spring urged detent adapted to be received within a cooperating depression within the square opening of the socket member.

While this detent type of retaining means has been employed for many years, it has been subject to disadvantages which have been tolerated up to" the present for want of a complete solution. One disadvantage of such detent types of retaining means has been that the springs which normally urge thedetent to projected re-- taining position have frequently failed, thereby releasing the detent and hence releasing the socket member from the spindle. Also, it has frequently happened that the detent and its spring sometimes became stuck .due to dirt or other causes or became cocked which rendered the application or removal of the socket member from the spindle quite diflicult, if not impossible. A further disadvantage was the necessity, in order to effect depression of the detent out of locking engagement with the socket member, of using a special tool which quite often was misplaced or unavailable for immedaite use.

Another disadvantage was that frequently the socket member and spindle retaining means were designed 'and dimensioned especially for each other so that the detent could properly engage within the retaining notch in the socket member at only a certain point, this proper psitioning of the socket member on the spindle being accomplished by providing a sharp right angle shoulder against which the rear face of the socket member was seated. The formation of this abrupt shoulder on the spindle resulted in a weakened construction whichoften caused the spindle to fracture during operation. Furthermore, because precise positioning was required, the spindle and retaining means were not capable of substantially universal application to socket members of various lengths and constructions.

It is, therefore, a principal object of our invention to provide a novel and improved retaining means for detachably securing a socket member or the like on a rotating spindle, which retaining means possesses none of the disadvantages of prior constructions.

Another object of our invention is to provide an improved form of spindle and retaining means for rotary power tools whereby socket members and the like :rnay be readily and quickly applied thereto or removed therefrom without the use of special tools and said socket means comprisingour invention;

is of simple, efficient and durable construction and which may be readily assembled with a minimum of effort. 1

Other objects and advantages of the invention will become apparent from the subsequent detailed description taken in conjunction with the accompanying drawing, wherein:

Figure l is a fragmentary side elevational view of the forward spindle end of a rotary power tool with a socket member, partially in longitudinal section, mounted thereon and showing one specific embodiment of the retainer Fig. 2 is an enlarged transverse sectional view taken on the line 22 in Fig. 1, looking rearwardly of the tool in the direction of the arrows;

Fig- 3 is an enlarged fragmentary, side elevational view of the forward end of the drive spindle of the rotary tool and the novel retaining means, the socket member being removed therefrom;

fore engagement therewith;

Fig. 5 is a fragmentary, longitudinal sectional view of the spindle and the retaining means in retaining position Within the square opening of the socket member;

Fig. 6 is a view of the retaining spring disassembled from the spindle and viewed: from the lower side thereof; and

Fig. 7 is a side elevational view of the retaining spring. ,Referring to thedrawings, there is shown the forward portion of a rotary tool spindle 10 having a polygonal or square end 11 which is adapted to project beyond the casing of the tool. The tool may be any one of anumber of types of rotary power tools such as nutsetters, impact tools and the likQxthG work-engaging or socket members for which are adapted to 'be placed over and .secured to the square 11. The socket member 12 has a polygonal or square opening 13 at its rearward end into which the spindle square 11 is received in a sliding fit and has an enlarged polygonal opening 14 at its forward end adapted to be placed over a bolt head or nut (not shown) for loosening or tightening the same. No v'notches or depressions are provided in the flat surfaces of the socket square opening 13. The rotary torque of the power tool is transmitted to the socket member 12 through the driving, non-slip engagement of the spindle square 11 within the complementary square opening 13 of the socket member. The spindle 10 is provided at its extreme forward 'or free end with 'a circular cap or head portion 16, the diameter of which is substantially the same size as the distance between the flat faces of the square 11. The spindle 10 also has a short annular neck portion 17 extending between the cap 16 and the square 11 thus-forming an annular groove 18, and in this groove there is positioned a coil spring 19 of novel construction which in combination with the spindle serves to retain the socket member 12 against longitudinal displacement and in driving engagement with the square 11. Y j

The retaining coil spring 19 is so formed that at its forward end adjacent the spindle cap 16 the forward coil is of reduced diameter and at itsrearward end the coil is of enlarged diameter. As shown in Figs. 6 and 7, the forward coil of the spring 19 when disassembled is of a smaller diameter than the diameter of the neck pormounted over-the neck portion 17 within the groove -18, the forward coil will be undertension in gripping engagement with the neck. This gripping engagement by the smaller forward coil serves to position or align "the retainingspring 19 properly withinthegroove 18 at all times and under all conditions of operation. To -;eifect this gripping engagement, the inner face of the forward free end 19a of the forward coil is in tight frictional engagement with the spindle neck 17 andthis tight frictional engagement is maintained for somewhat more than 180, at which point the coil commences to moveprogressively outwardlyaway; from the neck 17 until theouter surfaces 22, 23, 24 and 25 of the larger upper or rearward coil project beyond the outer limits of the four flat side surfaces of the square 11 as shown 'more particularly in Figs. 3- and 4. The rearward free end 19b of the spring 19 terminates :at a point spaced from the neck 17.

The sides of the forward and rearward ends 19a and 19b of the spring are flattened as shown particularly in Figs. 2, 3 and 4 so asto engage intimately the side faces of the groove 18. Also, as illustrated in Figs. 3 and 5, the-neck 17 is integrally joined to the cap 16 and to the .square 11 by annular fiillets 17a and 17b which serve to strengthen the construction and resist breakage or fracture of the cap 16 from the neck 17 and the neck 17 from the square 11.

It is imperative that the large upper or rearward coil of the spring 19 projects beyond the outer limits of the -flat side facesof the square 11 and it has been found in actual practice that the projection of the coil portions 22, 23, 24 and 25 to an extent of approximately .015 of an inch will afford satisfactory results provided, of course, that thesquare 11 and the square opening 13 of the socket are of a proper complementary sliding fit. In other words, the rearward coil; must project to such an. extent beyondthe fiat sides of the square 11 and be larger than the opening 13 of the socket member 12, as shown in Fig. 4,- as to-be placed-under compression when the socket member 12 is forced longitudinally thereover. Also .the forward or-smaller coilmust snugly and secure- -1y grip. the neck 17--under with a sufiicientdegree of tension so that the axis of the spring 19 will be maintained at all times coincidental with the axis of the neck 17. This causes the large coil to beheld properlyand to be evenly spaced from the neck 17 and toproject at its 1 four spacedpoints 22, 23, 24-and-25 about its circumference beyond the limits of the four flat faces of the .square 11.

When the socket member 12 has been removed from 'the spindle 10, the spring 19 assumes the uncompressed position shown in Pig.v 3. In the event the operator of the rotary power tooldesires to apply a socket member, such as-12, to the spindle 10, the socket member is initially moved rearwardly toward the square 11, the circular cap end 16 first entering the square opening 13. The cap 16 and the smaller forward coil of the spring 19 freely enter the square opening 13 until, as illustrated Ill] Fig. 4,-the rear verticalface bordering one side of the square opening 13 engages that portion of the spring coil immediately before ithas reached its first fully outward projected position at point 25. This initial contact facilitates entry of the spring and spindle into the square opening. The operator by the application of continued rearward force presses the socket member 12 against the spring 19 which becomes progressively compressed as the spring enters thesquareopening 13. The surface of these projecting spring portions 22, 23, 24 and-25 being rounded, the operator, upon the application of a rearward force by the socket member 12 against the 7 spring 19, cams the upper coil into compressed condition so that the large spring coil with the square 11 then 1 enters into the socket square 13 under compression.

As shown in Figs. 1, 2 and 5, the larger coil of the spring-19 bearsagainst the inner -flat surfaces of the However, with socket square 13 at four spaced points and because the forward or lower coil-is in tight gripping engagement with the spindle neck 17, the larger coil is positioned acurately within the socket square 13 even under compression. Hence, the expansive pressure of the spring 19 is applied substantially in equal amounts at equally spaced points within the socket square 13 and this results in a tight frictional engagement between the spring 19 and the socket member 12 which serves to retain the socket member- 12 inproper longitudinal position on the square 11.

It has been found thatalthoughthe frictional engagement between the spring 19 and the socket square 13 is of sufficient magnitude and character to prevent inadvertent removal of the socket member 12 during all normal operating conditions, nevertheless, the operator may readily remove the socket 12 by simply pulling it off the square with a minimum of effort.

As shown more particularly in Fig. l of the drawings, the square 11 is connected to the enlarged portion 20 of the spindle 10 by an integral annular fillet 21 which serves to greatly strengthen the spindle and square. Heretofore, with the detent type of retaining means, it has been necessary to form a sharp shoulder by joining the square directly at right angles to the enlarged spindle portion, this sharp shoulder being required to seat and engage the rearward end face of a socket member in order to locate properly and align the detent of the square with respect to the cooperating notch or groove in'the retaining square opening of the socket member. Thus, because such accurate positioning was required, such socket members were usable only with the spindles and retaining means for which theywere especially designed, and the spindle was not generally usable with socket members having square openings of varying lengths. the present spindle and retaining means, no preciseness of positioning is required of thespindle i and retaining means within the socket member, and the socket member need not be pushed up against the spindle shoulder 20, thus permitting the use of the strengthening fillet. It is only necessary that the square 11 be inserted into the socket square opening 13 a suflicient-extent to lprovide a firm driving engagement therewith and when this occurs the retaining spring 19 is also in proper retaining position.

From the foregoing it will be readily evident that the I present invention possesses benefits and. advantages not found in the retaining devices of the prior art. The

socket member or annular work piece may be quickly forced over and aifixed to the driving square by a forceful longitudinal movement in which position it is retained positively without any likelihood of removal or displacement therefrom during normal tool operation. No special tools are required to secure the socket memberon the square nor are any required to disengage the member to effect its removal. Moreover, the improved spindle and retaining means comprising the present invention may be utilized in conjunction with socket members having polygonal openings of A different longitudinal lengths since the retaining meansis substantially universal in its application and requires no I preciseness of fit or cooperation with any complementary retaining element in the socket square opening. All that is required is that the relationship between the socket opening and the retaining spring be such that there isa relatively tight frictional. engagement therebetween as above explained. The use of spring urged detents as .retaining means and their disadvantages has been eliminated-by the above-described spring means which is not subjectto misoperation or malfunctioning but which may be readily cleaned and inspected andwhich is capableof a long reliable life without the likelihood of failure.

Although theinvention has. been described in connectionwith-onespecific-embodiment, it will be understood that various equivalent structures and modifications may be resorted to without departing from the scope of the invention as defined in the appended claim.

We claim:

In combination, a rotary spindle adapted to project into and drive a work-engaging member and having an annular groove therein forming a spindle neck portion of reduced size, and means for detachably securing a work-engaging member on said spindle comprising a coil spring in said groove carried by and encircling said spindle neck portion and having a forward coil secured in tight gripping engagement with said spindle neck against lateral displacement relative thereto and a rearward coil spaced from said neck and having circumferential portions thereof extending beyond the peripheral limits of said spindle, said forward and rearward coils having their 15 6 outer sides flattened for intimate engagement with the adjacent radial side faces of the annular groove in the spindle, said rearward coil being adapted to be engaged and radially inwardly compressed by the interior of the work-engaging member to retain the same in operable position on the spindle.

References Cited in the file of this patent UNITED STATES PATENTS 1,475,136 Olson Nov. 20, 1923 1,800,254 Holmes Apr. 14, 1931 2,553,021 Von Adelung May 15, 1951 2,668,278 Avery Feb. 2, 1954 2,704,681 Fischer Mar. 22, 1955 

